To make a REALLY long story short:
When I was 3, my cousin and I used to have diaper fights and we'd whack each other with diapers. It was real fun. Then, when I was about 6, I would secretly sneak these luvs my sister had and wear them at night. A friend across the street had this Baby Born doll and all its accessories; we found it in his closet for some reason, probably left over from his sister or something. We found this diaper in its box, and I dared him to put it on. After going through 10 minutes of "No, you do it."'s, he put it between his crotch and pulled it up over his pants. Then he told me to do it, so I did. Then I dared him to actually put it on, and he did it in the bathroom. He told me it felt good, so I took it and tried it. Then, I asked him if he had anymore. He went into a closet downstairs and gave me these Huggies, probably leftover from when he was a baby. We went downstairs to his basement and would secretly put on the diapers and stuff like that. We did it whenever we went to his house. I guess that is when I started really liking diapers and how they felt. This is probably why I like baby diapers so much. Then, when I moved later on, my new next door neighbors had a 3 year old kid who was in diapers. I was friends with one of her brothers up there. He was about my age. We were talking about guy stuff, and he asked me what masturbation was and I didn't know. So he told me, and I told him that diapers feel really good. He went downstairs and got some of his sister's luvs and put one on. I didn't want to do it cause I thought it'd be weird in front of another guy at my age. He wore it and I think peed in it and said it felt real good, like I told him. His mom saw him and laughed at him, and told him to get out of the diaper. My friend thought it was the funniest thing ever. Then, later on in the years, I found one of his sister's baby born doll diapers in his basement during a sleepover. I took it and sneaked it back to my house. That's when I started masturbating with them and stuff like that. Basically that's how I started liking diapers in my extremely short-hand version of the story
I'd never tell my girlfriend this, though. Nobody I know personally knows this stuff. But boy, would I be happy if I told my girlfriend and she found it fine.